Physical Sciences and Mathematics | Open Access Articles

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Journal of the Iowa Academy of Science: JIAS

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Front Matter

Journal of the Iowa Academy of Science: JIAS

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Electromagnetic Reaction Cross Sections In Relativistic Heavy Ion Collisions, Jack Dostal

Presidential Scholars Theses (1990 – 2006)

The goal of this project was to produce a computer program to predict the cross section of relativistic heavy ion collisions between given projectile and target nuclei. An explanation of the usefulness of relativistic heavy ion collision analysis is presented. The use of the Weiszacker-Williams method of virtual quanta for enhancing reaction cross sections of this type is discussed. Quantum-mechanical corrections to the semiclassical Weiszacker-Williams method are introduced. C++ computer code has been developed to calculate both semiclassical (as a check) and quantum-mechanical cross sections for these types of reactions. Preliminary results are given for the heavy ion reaction ( …

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More Triangular Number Results, Bruce Brandt

Journal of the Minnesota Academy of Science

I define an increasing function from triangular numbers to triangular numbers and prove it preserves [mathematical symbol]. I conjecture that whether a triangular number is in the image of this function is related to the magnitude of [mathematical symbol] on the triangular number. Parallel theorems and conjectures exist for pentagonal numbers. I also make conjectures about the partial sums of [mathematical symbol] on the triangular numbers along with a conjecture about the sums of absolute values of [mathematical symbol] on the squares.

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On Translations Of Quadratic Residues, Bruce Brandt

Journal of the Minnesota Academy of Science

The question is posed: Given a set, S, and a positive integer, k, does a function from k to S exist such that, letting x - y if x is a member of a k-tuple going toy, we never have x - y and y - x? The question is linked to whether circular translations of quadratic residues intersect. Several conjectures are made related to the heuristic that quadratic residues are more inclined to intersect their circular translation than other subsets of Z/nZ with the same number of elements.

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Contributed Papers

Journal of the Minnesota Academy of Science

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Index

Journal of the Minnesota Academy of Science

No abstract provided.

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Winchell Papers

Journal of the Minnesota Academy of Science

Abstracts from the Winchell Papers given at the Annual Meeting for the Journal of the Minnesota Academy of Science.

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Winchell Posters

Journal of the Minnesota Academy of Science

Abstracts from the Winchell Posters given at the Annual Meeting for the Journal of the Minnesota Academy of Science.

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Eigenfunction And Harmonic Function Estimates In Domains With Horns And Cusps, Michael Cranston, Yi Li

Mathematics and Statistics Faculty Publications

No abstract provided.

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Travelling Fronts In Cylinders And Their Stability, Jerrold W. Bebernes, Comgming Li, Yi Li

Mathematics and Statistics Faculty Publications

No abstract provided.

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Properties Of Sun-Like Stars With Planets: 51 Pegasi, 47 Ursae Majoris, 70 Virginis, And Hd 114762, Gregory W. Henry, Sallie L. Baliunas, Robert A. Donahue, Willie H. Soon, Steven H. Saar

Information Systems and Engineering Management Research Publications

Radial velocity variations have revealed planets orbiting 51 Peg, 47 UMa, and 70 Vir, and a low-mass companion orbiting HD 114762. We analyze parallel records of photometric measurements in Strömgren b and y and Johnson V, R, and I passbands and Ca II H and K fluxes in those stars. In the case of 51 Peg, the high precision of the differential photometric measurements made by the 0.75 m Automatic Photoelectric Telescope and the nonvariability of the star would allow the detection of a transit of a planet as small as Earth (corresponding to an amplitude of 0.0001 mag) if …

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Properties Of Sun-Like Stars With Planets: Ρ1 Cancri, Τ Bootis, And Υ Andromedae, Sallie L. Baliunas, Gregory W. Henry, Robert A. Donahue, Francis C. Fekel, Willie Soon

Information Systems and Engineering Management Research Publications

Planets have been reported orbiting the Sun-like stars ρ¹ Cnc, τ Boo, and υ And based on low-amplitude radial velocity variations. We have derived information on the first two stars from analysis of spectra, as well as parallel records of high-precision Strömgren b and y photometry and Ca II H + K fluxes. In the case of ρ¹ Cnc, the upper limit (peak to peak) of nondetection of photometric variability at the orbital period is Δy ~ 0.0004 mag. The possibility of a planetary transit cannot be ruled out completely from the photometric data. Variations of the …

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The Nature Of Compact Galaxies In The Hubble Deep Field. Ii. Spectroscopic Properties And Implications For The Evolution Of The Star Formation Rate Density Of The Universe, Rafael Guzmán, Jesús Gallego, David C. Koo, Andrew C. Phillips, James D. Lowenthal, S. M. Faber, Garth D. Illingworth, Nicole P. Vogt

Astronomy: Faculty Publications

We present a spectroscopic study of 51 compact field galaxies with redshifts z < 1.4 and apparent magnitudes I < 23.74 in the flanking fields of the Hubble Deep Field. These galaxies are compact in the sense that they have small apparent half-light radii (r ≤ 0″.5) and high surface brightnesses (μ ≤ 22.2 mag arcsec ). The spectra, taken at the Keck telescope, show emission lines in 88% of our sample, and only absorption lines in the remaining 12%. Emission-line profiles are roughly Gaussian with velocity widths that range from the measurement limit of σ ∼ 35 km s to 150 km s . Rest frame [O II] λ3727 equivalent widths range from 5 to 94 Å, yielding star formation rates (SFRs) of ∼0.1 to 14 M yr . The analysis of various line diagnostic diagrams reveals that ∼60% of compact emission-line galaxies have velocity widths, excitations, Hβ luminosities, SFRs, and mass-to-light ratios characteristic of young star-forming H II galaxies. The remaining 40% form a more heterogeneous class of evolved starbursts, similar to local starburst disk galaxies. We find that, although the compact galaxies at z > 0.7 have similar SFRs per unit mass to those at z < 0.7, they are on average ∼10 times more massive. Our sample implies a lower limit for the global comoving SFR density of ∼0.004 M yr Mpc at z = 0.55, and ∼0.008 M yr Mpc at z = 0.85 (assuming Salpeter IMF, H = 50 km s Mpc , and q = 0.5). These values, when compared to estimates for a sample of local compact galaxies selected in a similar fashion, support a history of the universe in which the SFR density declines by a factor ∼10 from z = 1 to today. From the comparison with the SFR densities derived for magnitude-limited samples of field galaxies, we conclude that compact emission-line galaxies, though only ∼20% of the general field population, may contribute as much as ∼45% to the global SFR of the universe at 0.4 < z < 1. © 1997. The American Astronomical Society. All rights reserved. 814 1/2 I814 ⊙ ⊙ ⊙ 0 o -2 -1 -1 -1 -1 -3 -1 -3 -1 -1

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Keck Spectroscopy Of Redshift Z ∼ 3 Galaxies In The Hubble Deep Field, James Lowenthal, David C. Koo, Rafael Guzmán, Jesús Gallego, Andrew C. Phillips, S. M. Faber, Nicole P. Vogt, Garth D. Illingworth, Caryl Gronwall

Astronomy: Faculty Publications

We have obtained spectra with the 10 m Keck telescope of a sample of 24 galaxies having colors consistent with star-forming galaxies at redshifts 2 ≲ z ≲ 4.5 in the Hubble deep field (HDF). Eleven of these galaxies are confirmed to be at high redshift (z = 3.0), one is at z = 0.5, and the other 12 have uncertain redshifts but have spectra consistent with their being at z > 2. The spectra of the confirmed high-redshift galaxies show a diversity of features, including weak Lyα emission, strong Lyα breaks or damped Lyα absorption profiles, and the stellar and …

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Mobile Unity: A Language And Logic For Concurrent Mobile Systems, Peter J. Mccann, Gruia-Catalin Roman

All Computer Science and Engineering Research

Traditionally, a distributed system has been viewed as a collection of fixed computational elements connected by a static network. Prompted by recent advances in wireless communications rechnology, the emerging field of mobile computing is challenging these assumptions by providing mobile hosts with connectivity that may change over time, raising the possibility that hosts may be called upon to operate while only weakly connected to or while completely disconnected from other hosts. We define a concurrent mobile system as one where independently executing coponents may migrate through some space during the course of the computation, and where the pattern of connectivity …

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Reasoning About Code Mobility With Mobile Unity, Gian Pietro Picco, Gruia-Catalin Roman, Peter J. Mccann

All Computer Science and Engineering Research

Advancements in network technology have led to the emergence of new computing paradigms that challenge established programming practices by employing weak forms of consistency and dynamic forms of binding. Code mobility, for instance, allows for invocation-time binding between a code fragment and the location where it executes. Similarly, mobile computing allows hosts (and the software they execute) to alter their physical location. Despite apparent similarities, the two paradigms are distinct in their treatment of location and movement. This paper seeks to uncover a common foundation for the two paradigms by exploring the manner in which stereotypical forms of code mobility …

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Sequence Assembly Validation By Restriction Digest Fingerprint Comparison, Eric C. Rouchka, David J. States

All Computer Science and Engineering Research

DNA sequence analysis depends on the accurate assembly of fragment reads for the determination of a consensus sequence. Genomic sequences frequently contain repeat elements that may confound the fragment assembly process, and errors in fragment assembly, and errors in fragment assembly may seriously impact the biological interpretation of the sequence data. Validating the fidelity of sequence assembly by experimental means is desirable. This report examines the use of restriction digest analysis as a method for testing the fidelity of sequence assembly. Restriction digest fingerprint matching is an established technology for high resolution physical map construction, but the requirements for assembly …

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Master's Degree Programs In: Marine Environmental Sciences, Marine Biology, Coastal Zone Management 1997, Nova Southeastern University

Halmos College of Natural Sciences and Oceanography Course Catalogs

No abstract provided.

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A Proposed Solution For Word-Recognition Deficit In The Computer Environment, Hyacinth Williams

CCE Theses and Dissertations

Most college students with reading disabilities have difficulty with word recognition. The purpose of this study was to use an investigator-made cue word list to increase low word recognition skills among college students while creating slides for a university curriculum using a simple presentation tool. The investigator randomly divided fourteen subjects into two groups. One group received the treatment and the other did not. Subjects received fifty minutes to complete a five-slide presentation. The investigator used four different data collection processes for data collection. Beyond this, the investigator presented the results using rank correlation. Results from this study indicated that …

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The Total Cosmic Diffuse Gamma-Ray Spectrum From 9 To 30 Mev Measured With Comptel, S C. Kappadath, James M. Ryan, K Bennett, H Bloemen, R Diehl, W Hermsen, Mark L. Mcconnell, V Schonfelder, M Varendorff, G Weidenspointer, C Winkler

Space Science Center

A preliminary COMPTEL Cosmic Diffuse Gamma-Ray (CDG) spectrum from 800 keV to 30 MeV was presented earlier at the 3rd Compton Symposium. The COMPTEL results represent the first significant detection of the CDG radiation in the 9 to 30 MeV range. Using high-latitude data from the first 5 years of the mission we have performed a new detailed measurement of the 9 to 30 MeV spectrum with finer energy binning. The new improved results are in good agreement with our previous estimates and are compatible with power-law extrapolations from higher energies. The measured 9–30 MeV spectra from the Virgo and …

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The Mev Spectrum Of Cygnus X-1 As Observed With Comptel, Mark L. Mcconnell, K Bennett, H Bloemen, W Collmar, W Hermsen, L Kuiper, R Much, James M. Ryan, V Schonfelder, H Steinle, A W. Strong, R Vandijk

Space Science Center

The COMPTEL experiment on the Compton Gamma-Ray Observatory (CGRO) has observed the Cygnus region on several occasions since launch. These data represent the most sensitive observations to date of Cygnus X-1 in the 0.75–30 MeV range. The spectrum shows significant evidence for emission extending out to several MeV. These data alone suggest a need to modify the thermal Comptonization models or to incorporate some type of non-thermal emission mechanism. Here we report on the results of an analysis of selected COMPTEL data collected during the first three years of the CGRO mission. These data are then compared with contemporaneous data …

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A Search For Gamma-Ray Flares From Black-Hole Candidates On Time Scales Of ∼1.5 Hours, R Vandijk, K Bennett, H Bloemen, R Diehl, W Hermsen, Mark L. Mcconnell, James M. Ryan, V Schonfelder

Space Science Center

Strong short-lived flares from black-hole candidates have been detected in the hard X-rayregime and possibly also at γ-ray energies. Here we present a search for short-lived flares in the 0.75–30 MeV COMPTEL data. No flares are found during the 5 viewing periods considered, with typical upper limits of a few times the Crab flux.

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Comptel All-Sky Imaging At 2.2 Mev, Mark L. Mcconnell, S Fletcher, K Bennett, H Bloemen, R Diehl, W Hermsen, James M. Ryan, V Schonfelder, A W. Strong, R Vandijk

Space Science Center

It is now generally accepted that accretion of matter onto a compact object (white dwarf, neutron star or black hole) is one of the most efficient processes in the universe for producing high energy radiations. Measurements of the γ-ray emission will provide a potentially valuable means for furthering our understanding of the accretion process. Here we focus on neutroncapture processes, which can be expected in any situation where energetic neutrons may be produced and where the liberated neutrons will interact with matter before they decay (where they have a chance of undergoing some type of neutron capture). Line emission at …

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Reassessment Of The 56co Emission From Sn 1991t, D Morris, K Bennett, H Bloemen, R Diehl, W Hermsen, G G. Lichti, Mark L. Mcconnell, James M. Ryan, V Schonfelder

Space Science Center

The detection of 56Co emission from SN 1991T has been previously reported at a level near the COMPTEL sensitivity threshold. The spectral analysis method, fitting the count spectrum to a background model plus a 56Co emission template, is subject to possible systematic effects which had not been thoroughly studied at that time. To better evaluate the significance of that ∼3.3σ detection, the same method has been applied to a grid of points with 5° spacing, out to 35° from the pointing direction, in each of 103 observing periods from phases 1 through 3. A dozen instances were found with a …

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A Time Dependent Model For The Activation Of Comptel, M Varendorff, U Oberlack, G Weidenspointer, R Diehl, R Vandijk, Mark L. Mcconnell, James M. Ryan

Space Science Center

The structure of the CGRO satellite is irradiated by cosmic rays and trapped particles fromradiation belts. These incident particles produce radioactive nuclei in nuclear reactions with the satellite structure. Most of the radiation dose can be attributed to the passages through the South Atlantic Anomaly. The incident particle flux on the COMPTEL instrument is estimated from the event rate of a plastic scintillation detector. This event rate is modeled with a Neural Network simulation. The increase of the event rate during SAA passages is taken as a measure for the amount of induced radioactivity. A Neural Network Model is used …

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Diffuse Galactic Continuum Emission: Recent Studies Using Comptel Data, A W. Strong, R Diehl, V Schonfelder, K Bennett, Mark L. Mcconnell, James M. Ryan

Space Science Center

COMPTEL full sky maximum entropy maps using 5 years of data have been produced using background estimates based on high-latitude observations. The Galactic diffuse emission can be studied using latitude and longitude profiles from these maps. Direct comparison of profiles with theoretical models is illustrated for the 10–30 MeV range. We demonstrate the presence of a broad latitude component, consistent with results from model-fitting studies. The method is also used to obtain model-independent broad-band spectra of the Galactic emission.

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On The Level Crossing Of Multi-Dimensional Delayed Renewal Processes, Jewgeni H. Dshalalow

Mathematics and System Engineering Faculty Publications

The paper studies the behavior of an (l+3)th-dimensional, delayed renewal process with dependent components, the first three (called active) of which are to cross one of their respective thresholds. More specifically, the crossing takes place when at least one of the active components reaches or exceeds its assigned level. The values of the other two active components, as well as the rest of the components (passive), are to be registered. The analysis yields the joint functional of the crossing level and other characteristics (some of which can be interpreted as the first passage time) in a closed form, refining earlier …

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Monotone Iterations For Differential Equations With A Parameter, Tadeusz Jankowski, V. Lakshmikantham

Mathematics and System Engineering Faculty Publications

Consider the problem {y′(t)=f(t,y(t),λ),t∈J=[0,b],y(0)=k0,G(y,λ)=0. Employing the method of upper and lower solutions and the monotone iterative technique, existence of extremal solutions for the above equation are proved.

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Real Time 3-D Video Moire Inspection System With Enhanced Depth Resolution, Donald W.W. Dawson, Chris L. Hart, Bernard R. Gilbert, Gary L. Wallace, Joel H. Blatt

Aerospace, Physics, and Space Science Faculty Publications

A variable resolution video machine vision systems has been built which generates twice the number of depth contours for a given grating spacing as a conventional moiré system. This variable resolution system uses a Mach-Zender interferometer to project interference fringes onto a reference surface and onto a target surface. Video images of the two structurally illuminated surfaces are mixed in a video mixer with the resulting output being moiré contours which are the intersections of the two surfaces. If the reference surface is a flat plate, we get equal depth contours of the target surface, and if the reference surface …

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Full-Text Articles in Physical Sciences and Mathematics

Back Cover

Journal of the Iowa Academy of Science: JIAS

Front Matter

Journal of the Iowa Academy of Science: JIAS

Electromagnetic Reaction Cross Sections In Relativistic Heavy Ion Collisions, Jack Dostal

Presidential Scholars Theses (1990 – 2006)

More Triangular Number Results, Bruce Brandt

Journal of the Minnesota Academy of Science

On Translations Of Quadratic Residues, Bruce Brandt

Journal of the Minnesota Academy of Science

Contributed Papers

Journal of the Minnesota Academy of Science

Index

Journal of the Minnesota Academy of Science

Winchell Papers

Journal of the Minnesota Academy of Science

Winchell Posters

Journal of the Minnesota Academy of Science

Eigenfunction And Harmonic Function Estimates In Domains With Horns And Cusps, Michael Cranston, Yi Li

Mathematics and Statistics Faculty Publications

Travelling Fronts In Cylinders And Their Stability, Jerrold W. Bebernes, Comgming Li, Yi Li

Mathematics and Statistics Faculty Publications

Properties Of Sun-Like Stars With Planets: 51 Pegasi, 47 Ursae Majoris, 70 Virginis, And Hd 114762, Gregory W. Henry, Sallie L. Baliunas, Robert A. Donahue, Willie H. Soon, Steven H. Saar

Information Systems and Engineering Management Research Publications

Properties Of Sun-Like Stars With Planets: Ρ1 Cancri, Τ Bootis, And Υ Andromedae, Sallie L. Baliunas, Gregory W. Henry, Robert A. Donahue, Francis C. Fekel, Willie Soon

Information Systems and Engineering Management Research Publications

Astronomy: Faculty Publications

Keck Spectroscopy Of Redshift Z ∼ 3 Galaxies In The Hubble Deep Field, James Lowenthal, David C. Koo, Rafael Guzmán, Jesús Gallego, Andrew C. Phillips, S. M. Faber, Nicole P. Vogt, Garth D. Illingworth, Caryl Gronwall

Astronomy: Faculty Publications

Mobile Unity: A Language And Logic For Concurrent Mobile Systems, Peter J. Mccann, Gruia-Catalin Roman

All Computer Science and Engineering Research

Reasoning About Code Mobility With Mobile Unity, Gian Pietro Picco, Gruia-Catalin Roman, Peter J. Mccann

All Computer Science and Engineering Research

Sequence Assembly Validation By Restriction Digest Fingerprint Comparison, Eric C. Rouchka, David J. States

All Computer Science and Engineering Research

Master's Degree Programs In: Marine Environmental Sciences, Marine Biology, Coastal Zone Management 1997, Nova Southeastern University

Halmos College of Natural Sciences and Oceanography Course Catalogs

A Proposed Solution For Word-Recognition Deficit In The Computer Environment, Hyacinth Williams

CCE Theses and Dissertations

The Total Cosmic Diffuse Gamma-Ray Spectrum From 9 To 30 Mev Measured With Comptel, S C. Kappadath, James M. Ryan, K Bennett, H Bloemen, R Diehl, W Hermsen, Mark L. Mcconnell, V Schonfelder, M Varendorff, G Weidenspointer, C Winkler

Space Science Center

The Mev Spectrum Of Cygnus X-1 As Observed With Comptel, Mark L. Mcconnell, K Bennett, H Bloemen, W Collmar, W Hermsen, L Kuiper, R Much, James M. Ryan, V Schonfelder, H Steinle, A W. Strong, R Vandijk

Space Science Center

A Search For Gamma-Ray Flares From Black-Hole Candidates On Time Scales Of ∼1.5 Hours, R Vandijk, K Bennett, H Bloemen, R Diehl, W Hermsen, Mark L. Mcconnell, James M. Ryan, V Schonfelder

Space Science Center

Comptel All-Sky Imaging At 2.2 Mev, Mark L. Mcconnell, S Fletcher, K Bennett, H Bloemen, R Diehl, W Hermsen, James M. Ryan, V Schonfelder, A W. Strong, R Vandijk

Space Science Center

Reassessment Of The 56co Emission From Sn 1991t, D Morris, K Bennett, H Bloemen, R Diehl, W Hermsen, G G. Lichti, Mark L. Mcconnell, James M. Ryan, V Schonfelder

Space Science Center

A Time Dependent Model For The Activation Of Comptel, M Varendorff, U Oberlack, G Weidenspointer, R Diehl, R Vandijk, Mark L. Mcconnell, James M. Ryan

Space Science Center

Diffuse Galactic Continuum Emission: Recent Studies Using Comptel Data, A W. Strong, R Diehl, V Schonfelder, K Bennett, Mark L. Mcconnell, James M. Ryan

Space Science Center

On The Level Crossing Of Multi-Dimensional Delayed Renewal Processes, Jewgeni H. Dshalalow

Mathematics and System Engineering Faculty Publications

Monotone Iterations For Differential Equations With A Parameter, Tadeusz Jankowski, V. Lakshmikantham

Mathematics and System Engineering Faculty Publications

Real Time 3-D Video Moire Inspection System With Enhanced Depth Resolution, Donald W.W. Dawson, Chris L. Hart, Bernard R. Gilbert, Gary L. Wallace, Joel H. Blatt

Aerospace, Physics, and Space Science Faculty Publications